An unrestricted workpiece has six degrees of freedom with respect to the axes of the coordinate system of which three are along-axis-moving degrees and three are around-axis-revolving degrees. For the workpiece to be machined, the relative degrees of freedom must be restricted by a jig or fixture. So, evidently, if any workpiece is to be fixed in a modular tooling system, the interlocking features of the system must be able to freely move along and revolve around the axes for the features to be adjusted where they are necessary for constructing fixture bodies and fixing locators or clamps. In other words, a good modular tooling system should have two types of adjustability, along and around the coordinate axes. Since the advantage of slots is that they offer adjustability along axes, and holes offer adjustability around axes, the available hole-type modular tooling system must be advanced to offer the full adjustability by:
(a) introducing slots into the hole-type system to solve the problem of adjustability along axes, and PA1 (b) bringing the advantage of adjustability around hole axes into full play.
The solution of adjustability along axes is covered by this patent application, and around axes is covered in U.S. patent application Ser. No. 315,409 now U.S. Pat. No. 4,961,268.
Since the above-discussed principles for modularizing of jigs and fixtures are advanced by the inventors after their thorough study of the available modular tooling technology, this invention is a result of the available technology developing from the perceptual to the rational stage.
In the slot-type modular system, slots, as is known, are available, but they can neither make the slot-type system to provide continuous adjustability along them because of crossing, nor can they permit precise and fast setups because of the problem of rigging and indicating. In the conventional hole-type system, almost no proper slots have been introduced, to say nothing of overcoming the disadvantages of slots appearing in the slot-type system.